The effects of beta-estradiol on Raf activity, cell cycle progression and growth factor synthesis in the MCF-7 breast cancer cell line

The aim of this study was to test the hypothesis that some of the proliferative effects of steroid hormones on cancer cells are mediated by the Raf proto-oncogenes. The human breast cancer cell line MCF-7 is estrogen-receptor (ER) positive (+). NCI/ADR-RES is a human cell line lacking the estrogen receptor (ER-) that was initially named MCF-ADR. Raf-1, A-Raf and B-Raf kinase activities were examined in cell lines treated with beta-estradiol for 24 hours. Increases in Raf-1 and A-Raf activities were observed after treatment with beta-estradiol in the ER (+) MCF-7 cells but not in the ER (-) NCI/ADR-RES cells. In contrast, no significant changes in B-Raf activity were observed. Thus beta-estradiol can induce Raf-1 and A-Raf activities in ER (+) cells. In addition, beta-estradiol caused cell cycle progression in MCF-7 cells and an increased proliferative response to beta-estradiol was observed in MCF-7, which overexpressed constitutively-active Raf-1 (MCF/DeltaRaf-1). Increased mRNA levels of the ligand for the c-erb-B2 receptor, amphiregulin (ARG) were observed after beta-estradiol treatment of MCF-7 cells whereas constitutively higher levels of ARG and its receptor, c-erb-B2 mRNAs were detected in MCF/DeltaRaf-1 cells. These findings suggest that targeting Raf may prove efficacious in breast cancer therapies.

Effect of reproductive hormones on ovarian epithelial tumors: II. Effect on angiogenic activity

Menstrual cycle activity predisposes to ovarian epithelial tumors based on numerous epidemiological studies. We showed that the hormones involved in menstrual cycle regulation modulate cell cycle activity in these tumors in an accompanying paper. We investigated whether such hormones could also influence angiogenesis, an important determinant of tumor progression, in the same tumors. Treatment with progesterone (P4) stimulated VEGF protein secretion in 4 of 5 ovarian carcinoma cell lines examined. Northern blot analyses performed in MCV50 cells showed that this effect was accompanied by increased VEGF mRNA levels. P4 also stimulated VEGF promoter activity in these cells. Estradiol (E2) showed a similar, but substantially smaller effect on VEGF secretion which was additive to that of P4. Conditioned medium from P4-treated cells strongly stimulated angiogenesis on chicken chorio-allantoic membranes. Incubating the conditioned medium with a neutralizing anti-VEGF antibody, but not with non-specific immunoglobulins abolished this effect. Angiogenic activity was not altered by treatment of the membranes with P4 directly. We conclude that P4 can stimulate angiogenic activity via induction of VEGF secretion in some ovarian epithelial tumors. Therapeutic use of progestins may be most effective when administered in combination with an anti-angiogenic agent, at least against a subset of ovarian carcinomas.

[Expression of vascular endothelial growth factor in bone marrow cells of patients with acute myeloid leukemia]

OBJECTIVE

To investigate the role of vascular endothelial growth factor (VEGF) in the pathogenesis and progression of acute myeloid leukemia (AML).

METHODS

Reverse transcription-polymerase chain reaction (RT-PCR) was employed for VEGF mRNA detection. VEGF levels in the bone marrow cell cultural supernatant and plasma from normal subjects and AML patients were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

VEGF mRNA expression was present in most of the AML cell lines HL-60, K562 and Raji, but not in Jurkat cells. The expression rate of VEGF mRNA in the bone marrow cells from AML patients (82%) was higher than the rates in normal subjects (30.76%) and AML patients with autologous bone marrow transplantation (41.67%). Refractory and non-refractory AML patients had higher mean plasma VEGF levels than the normal donors and AML patients with transplantation did, without significant differences observed in the latter 2 groups. With also significant difference between them, refractory and non-refractory AML groups had respectively 11.0 and 7.3-fold higher VEGF levels in the culture supernatant than the normal donor group did.

CONCLUSION

The abnormality of VEGF expression may play an important role in the development of AML, and VEGF expression might be used as one of the indexes for prognostic assessment for AML patients.

VEGF gene therapy for coronary artery disease and peripheral vascular disease

Coronary artery disease (CAD) and peripheral arterial disease (PAD) are significant medical problems worldwide. Although substantial progress has been made in prevention as well as in the treatment, particularly of CAD, there are a large number of patients, who despite maximal medical treatment have substantial symptomatology and who are not candidates for mechanical revascularization. Therapeutic angiogenesis represents a novel, conceptually appealing treatment option. Ad(GV)VEGF121.10 (BIOBYPASS) is an adenovector, carrying the transgene encoding for human vascular endothelial growth factor 121 (VEGF(121)). A number of preclinical studies have demonstrated angiogenic activity of BIOBYPASS, not only anatomically but also functionally. Phase I clinical studies have demonstrated that intramyocardial infection of BIOBYPASS in patients with severe CAD as well as intramuscular injections of BIOBYPASS in patients with severe peripheral vascular disease (PVD) was well tolerated; furthermore, these studies provided some intriguing indications of activity, which led to initiation of major randomized Phase II "proof-of-concept" studies. This paper provides a review of the rationale behind BIOBYPASS as well as a summary of pertinent preclinical and early clinical data.

[Gene expression of insulin-like growth factors in human villous trophoblast cells of early pregnancy in vitro]

OBJECTIVE

To investigate the gene expression of insulin-like growth factors(IGFs) in human villous trophoblast cells of early pregnancy in vitro and their action.

METHODS

Semiquantitative reverse transcriptase polymerase chain reaction(RT-PCR), with beta-ACTIN as internal standard, was applied to determine the expression of IGFs messenger RNA in human villous trophoblast cells of early pregnancy in vitro.

RESULTS

The expression of IGF-II mRNA, IGF-I R mRNA and IGFBP-3 mRNA was detectable in human villous trophoblast cells of early pregnancy in vitro.

CONCLUSION

IGFs appear to play important regulation roles in early invasion, proliferation and differentiation of cytotrophoblast, and in the formation of placenta and the development of embryo via autocrine and/or paracrine way.

Differential C-erbB-2 and VEGF expression following BCG immunotherapy in superficial papillary transitional cell carcinoma of the bladder

Bacillus Calmette Guerin (BCG) is generally regarded as an effective immunotherapy for superficially invasive papillary transitional cell carcinoma of the bladder. The exact mechanism(s) which underlie its efficacy are unknown. As C-erbB-2 oncoprotein and vascular endothelial growth factor (VEGF) have been shown to be over-expressed in TCC of the bladder, it has been postulated that they may be important in its pathogenesis. The purpose of this study was to 1.) differentially evaluate the effect of BCG immunotherapy in treated and untreated cohorts on the immunohistochemical expression of C-erbB-2 and VEGF in formalin-fixed paraffin-embedded sections of superficial and superficially invasive (Stage Ta-T1) transitional cell carcinoma of the bladder. Immunolabeling intensity was assessed independently by two pathologists and reported as a mean labeling index. The results confirm previous studies that 1.) both c-erbB-2 and VEGF are over-expressed in these tumors MLI = 90.1 and 45.7 respectively, 2.) that VEGF is an early and sensitive indicator of TCC, and 3.) that BCG has a salutary effect on papillary TCC, 66% vs. 89% recurrence rate, P = .04. Our findings show that 1.) C-erbB-2 expression is decreased in patients tumors which show response to BCG (45.7 to 38.5), P = 0.15, 2.) that BCG administration has no effect on the expression of VEGF. While the decrement in c-erbB-2 immunostaining observed in those patients who received BCG contrasts with the increase in c-erbB-2 immunolabeling observed in patients who did not receive BCG, the differences were not statistically significant and could reflect tumor grade or stage regression associated with BCG therapy. However, this study suggests that BCG differentially influences the expression of C-erbB-2 and VEGF.

[Inhibitation of tumor angiogenesis, growth and metastasis by blocking VEGF paracrine pathway]

Solid tumors require an adequate vascular supply to grow beyond a certain dimension. It is known that formation of new blood vessels in tumor is mediated by unbalanced expression of angiogenic factors and their inhibitors. Among the former, the vascular endothelial growth factor (VEGF) has been assumed prime candidacy as a major positive physiological effector. To investigate the role of VEGF in angiogenesis associated with development of breast cancer, a sense VEGF and an anti-sense VEGF expression plasmids were constructed, and then were introduced into a human breast carcinoma cell line, MCF-7, expressing middle level of endogenous VEGF. Anti-sense VEGF(121) transfected MCF-7 cells that expressed reduced constitutive levels of VEGF and showed the same growing potential as untransfected MCF-7 cells in vitro, but it showed longer latency, smaller tumor, slower growth and prolonged survival time compared to parental or sense VEGF(165) transfected MCF-7 cells in vivo. Moreover, the tumors derived from anti-sense VEGF(121) transfected MCF-7 cells characterized by minimal vascularization and extensive necrosis. Finally, mice with primary subcutaneous tumors treated with intratumoral administration of anti-sense VEGF, or the plasmid expressing extracellular domain of the Flk-1 VEGF receptor (sFlk-1) followed by electroporation, showed significant tumor suppression. These results suggest that VEGF plays a major angiogenic role in breast cancer and a strategy, which blocks the VEGF paracrine pathway, may provide a means to control tumor growth topically without the risk of systemic antiangiogenesis.

Vascular endothelial growth factor gene regulation and action in diabetic retinopathy

It is conceivable that VEGF inhibition may prevent edema formation at the early stages of diabetic retinopathy. Once the retina is irreversibly ischemic or new vessels have formed, however, antagonizing VEGF may lead to retinal necrosis due to chronic ischemia. An alternative approach would be the induction of neovascular maturation. Once the new vessels become mature, retina ischemia resolves. There would be no edema, hemorrhage, or retinal detachment. Acute administration of an angiogenic molecule called angiopoietin-1 protects vasculature from leaking [103]. Angiopoietins bind to the endothelial cell-specific receptor Tie 2 and play an important role is vascular development, especially vessel maturation. The proposed mechanisms include recruiting pericytes and organizing vascular matrix [103]. Since VEGF is constitutively expressed at low levels in normal eyes [46], it may contribute to the maintenance of vascular integrity. Thus, oversuppression of VEGF expression may be harmful to the retinal vasculature. Inhibiting VEGF action may need to be delivered in a tightly regulated manner such that complete inhibition may be avoided both to maintain basal levels and to provide rapid reversal of inhibition when acute angiogenic responses are desired [72]. VEGF is involved in normal angiogenic processes in adults such as cardiac collateral circulation, wound healing and menstrual cycle [27]. Local drug delivery seems to be more appealing than systemic administration to avoid the side effects. Some VEGF antagonists, such as VEGF receptor chimeric protein and the VEGF neutralizing antibodies are large molecules with poor diffusion into tissues. Repetitive invasive procedures such as intravitreal injection seem to be impractical due to potential complications of retinal detachment and bacterial infection. Recent progress on transscleral delivery of bioactive proteins and DNAs to the choroid and retina provides promising future on local delivery of therapeutic agents [12,13].

[Upregulation of vascular endothelial growth factor by peroxide in human colon cancer]

OBJECTIVE

To clarify the possible effect of reactive oxygen species such as hydrogen peroxide on progression of human colorectal cancer.

METHOD

Human colon carcinoma cell lines, L174T and HCT8, were treated with low concentration of hydrogen peroxide (10(-5) mol/L, 10(-7) mol/L and 10(-9) mol/L, possessed no effect on cancer cell growth) for 24 hours before being co-cultured with human endothelial cell line ECV-304. The migration of ECV-304 induced by cancer cells was calculated and the expression of vascular endothelial growth factor (VEGF) in cancer cells was determined using RT-PCR and ELISA. Dactinomycin (1.5 microg/ml) was applied to block the transcription of cancer cell so as to observe the effect site of cell. Finally the activity of NF-KappaB of cancer cells was estimated using laser scanning cytometry.

RESULTS

Exogenous hydrogen peroxide of low concentration promoted the migration of endothelial cell induced by colon cancer cell. When the concentration of H(2)O(2) was 10(-5) mol/L, the average number of migration of endothelial cell induced by LS174T was 202.6 +/- 70.2, higher than the value of 154.6 +/- 37.9 when no H(2)O(2) was given (t = 3.4751, P = 0.0083). When the concentration of H(2)O(2) was 10(-5) mol/L, the average number of migration of endothelial cell induced by HCT8 was 145.4 +/- 65.3, higher than the value of 113 +/- 72.7 when no H(2)O(2) was given (t = 4.4183, P = 0.0084). The expression of vascular endothelial growth factor in cancer cells was enhanced to a certain degree, which could be blocked by Dactinomycin. And the half-time of VEGF mRNA was not prolonged by treatment with hydrogen peroxide. The activity of NF-KappaB of both colon carcinoma cell lines was at a higher level after being treated with hydrogen peroxide for 24 hours.

CONCLUSION

Hydrogen peroxide increases vascular endothelial growth factor expression in colon cancer cell, and it is possible that such reactive oxygen species as hydrogen peroxide facilitates development of colon cancer.

Connective tissue growth factor in the ovarian paracrine system

The endocrine actions of follicle stimulating hormone and luteinising hormone on ovarian cells are transduced by locally produced paracrine factors that regulate the formation of extracellular matrix, proteolytic enzymes and protease inhibitors, which continuously remodel the parenchymal environment in which follicles develop. We recently identified connective tissue growth factor (CTGF) as a gene expressed during the predifferentiated stage of granulosa cell development in rat ovary. The CTGF gene encodes a protein that is implicated in the regulation of connective tissue synthesis, mototaxis, angiogenesis and cellular interaction with ECM at various sites in the body. Stimulation of granulosa cells by FSH in vitro and in vivo induces follicular maturation associated with down-regulation of granulosa cell CTGF mRNA expression. The gene remains expressed in cells of the innermost (antrally located) granulosa compartment up to and after the point of ovulation. Based on the inferred biological properties of CTGF protein and the spatiotemporal pattern of CTGF mRNA expression in the ovary, we postulate roles for ovarian CTGF during early stages of follicular development and after ovulation in the formation of the corpus luteum.

The prognostic value of metalloproteinases and angiogenic factors in ovarian carcinoma

The objective of this study was to analyze the correlation between matrix metalloproteinases (MMPs) and angiogenic genes and survival in advanced-stage ovarian carcinomas. Primary and metastatic ovarian carcinomas from patients diagnosed with FIGO stage III-IV disease and followed up to 20 years were studied using mRNA in situ hybridization (ISH). Expression of MMP-2, MMP-9, membrane-type 1-MMP (MT1-MMP), the MMP inhibitor TIMP-2, vascular endothelial growth factor (VEGF), interleukin-8 (IL-8) and basic fibroblast growth factor (bFGF) was studied. MMP-2, MMP-9 and TIMP-2 mRNA was detected in both tumor and stromal cells, while MT1-MMP was largely confined to tumor cells. In univariate analysis of primary tumors, TIMP-2 and MMP-9 mRNA expression correlated with poor outcome. In metastatic lesions, mRNA expression of TIMP-2, MMP-2, and MT1-MMP correlated with poor survival. In a multivariate analysis of primary tumors, TIMP-2 expression in stromal cells (P=0.006) and MMP-9 expression in tumor cells (P=0.011) retained their predictive value. Intense expression of bFGF mRNA and weak expression of IL-8 mRNA was detected in both stromal and tumor cells in most cases, while VEGF mRNA expression was limited to a few cases. Angiogenic mRNA expression showed no correlation with disease outcome in survival analysis (P>0.05). We conclude that bFGF is the major angiogenic factor expressed in ovarian carcinoma at the mRNA level. MMP-2, MMP-9, MT1-MMP and TIMP-2 are valid markers of poor survival in advanced-stage ovarian carcinoma.

[Cloning of expression vector for VEGF121 and VEGF165 genes encoding human vascular endothelial growth factor]

OBJECTIVE

To clone and construct the expression vector for human vascular endothelial growth factor (VEGF) genes.

METHODS

Total RNAs were extracted from human lung tissue of a 4-month-old fetus and subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) with the amplified products cloned into pMD18-T vector. Sequence analysis was performed before the amplified products were cloned into the expression plasmid pcDNA3.1-, the recombinant of which was verified by endonuclease digestion.

RESULTS

After RT-PCR using a pair of primers (sense -21/7 bp and antisense 554/576 bp), two bands were identified. The band (487 bp) shorter in length was confirmed as VEGF121 (with the full length of VEGF121 being 444 bp) while the longer band (619 bp) was normal VEGF165 (with the full length of VEGF165 being 576 bp). Interestingly, another slightly longer VEGF165 nucleotide sequence was identified by sequencing analysis, which featured an unique 20 bp insertion precisely between exon 3 and exon 4 from the first ATG of human VEGF165 cDNA. The 20 bp insert was identified as the retaining intron 3 terminal nucleotides containing the splicing signal, which caused frame shift mutation in the reading frame and could probably give rise to a short polypeptides consisting of only 97 amino acid residuals due to the early appearance of stop code UAG in the middle of exon 4.

CONCLUSION

We have successfully constructed the expression vector for VEGF121 and VEGF165 genes, and a new possible alternative splicing isoform of VEGF is identified in normal fetus whose molecular mechanism and physiological function needs further investigation.

[Experimental study of anti-VEGF hairpin ribozyme gene inhibiting expression of VEGF and proliferation of ovarian cancer cells]

BACKGROUND & OBJECTIVE

Growth of solid tumor metastases are critically dependent on angiogenesis. Vascular endothelial growth factor (VEGF), also known as vascular permeability factor, has been identified as one of the most potent inducers of tumor associated angiogenesis, studies have shown that VEGF plays an important role in angiogenesis which is associated with epithelial ovarian cancer. Until now, many strategies for gene therapy have been developed. Among them is Ribozyme-based therapeutics for cancer which might be devised to inhibit tumor growth or prevent metastases. Angiogenesis is required for sustained tumor growth, making the VEGF pathway another promising target for either small molecule or nucleic acid-based therapeutics. Little is known about the role of VEGF in ovarian tumorigenecity. We propose to block the autocrine and/or paracrine pathway of VEGF in ovarian cancer using anti-VEGF hairpin ribozyme gene to see whether the growth of tumor cells could be inhibited and to further exploit its mechanisms.

METHODS

Anti-VEGF hairpin ribozyme gene eukaryotic expression vector was introduced into ovarian cancer SKOV3 cells by lipofectin mediation and positive clones were screened by G418; Ribozyme expression was confirmed by RNA dot blot; The VEGF expression of SKOV3 cells before or after transfection were detected by immunohistochemical and immunofluorescence and flow cytometer immunofluorescence methods, MTT, colony forming, soft agar colony forming, and FCM were used to observe the effect of proliferation to ovarian cancer cells.

RESULTS

VEGF expression decreased distinctly in SKOV3-RZ cells. The growth of transfected SKOV3-RZ cells were slower, The average colony forming efficiency and soft agar colony forming efficiency of SKOV3-RZ cells(12.7 +/- 1.4 and 9.4 +/- 2.0, respectively) decreased distinctly (P < 0.001). The SKOV3-RZ cells of G1 stage increased(P < 0.01), the SKOV3-RZ cells of S stage were reduced(P < 0.01).

CONCLUSIONS

Anti-VEGF hairpin ribozyme gene can inhibit the proliferation of ovarian cancer SKOV3 cells. This provides a experimental basis for cure human ovarian cancer with antiangiogenesis method.

Fusion of the NUP98 gene with the LEDGF/p52 gene defines a recurrent acute myeloid leukemia translocation

BACKGROUND

The NUP98 gene is involved in multiple rearrangements in haematological malignancy. The leukemic cells in an acute myeloid leukemia (AML) patient with a t(9;11)(p22;p15) were recently shown to have a fusion between the NUP98 gene and the LEDGF gene but it was not demonstrated that this fusion was recurrent in other leukaemia patients with the same translocation.

RESULTS

We used RT-PCR to analyse the leukemic cells from an AML patient who presented with a cytogenetically identical translocation as the sole chromosomal abnormality. A NUP98-LEDGF fusion transcript was observed and confirmed by sequencing. The reciprocal transcript was also observed. The fusion transcript was not detectable during remission and recurred at relapse. The breakpoints in the NUP98 and LEDGF genes were different to those previously reported. The NUP98 breakpoint occurs in the intron between exons 8 and 9. It is the most 5' breakpoint reported in a translocation involving the NUP98 gene. All of the LEDGF gene is included in the fusion except for exon 1 which codes for the first 24 amino terminal amino acids.

CONCLUSIONS

Our results show that fusion of the NUP98 and LEDGF genes is a new recurrent translocation in AML.

Regulation of growth-regulated oncogene alpha expression by estrogen in human endothelial cells

AIM

To study the effect of estrogen on expression of growth-regulated oncogene alpha (GROalpha) in human umbilical vein endothelial cells (HUVEC) in vitro.

METHODS

Expressions of CXC chemokine GROalpha mRNA and protein were measured by Northern blotting assay and ELISA, respectively. The physiological significance of GROalpha expression was tested by static cell adhesion assay.

RESULTS

Both the GROalpha mRNA and protein levels decreased markedly after HUVEC were exposured to 17beta-estradiol (2 0.05 micromol/L. Moreover, the inhibition of the protein was depended on the concentration of 17beta-estradiol. Tamoxifen (0.1 micromol/L), an estrogen receptor alpha antagonist, alone did not affect GROalpha protein expression, but can reverse the E2 -induced inhibition of GROalpha protein expression (by up to 50 %) and the binding of U937 cells to E2-treated HUVEC (by up to 40 %).

CONCLUSION

Estrogen might functionally down-regulates GROalpha expression through estrogen receptor alpha on endothelial cells.

A precursor form of vascular endothelial growth factor arises by initiation from an upstream in-frame CUG codon

Vascular endothelial growth factor (VEGF) is a mitogen in physiological and pathological angiogenesis. Understanding the expression of different VEGF isoforms might be important for distinguishing angiogenesis in tissue development, vascular remodelling and tumour formation. We examined its expression and noted the presence of the isoforms VEGF(121) and VEGF(165) (121 and 165 residues long respectively) in fetal heart, lung, ovary, spleen, placenta and ovarian tumours. Unexpectedly, a 47 kDa species predominated in fetal intestine and muscle. The presumed initiation site in VEGF is an AUG codon (AUG(1039)), 1039 nt from its main transcriptional start site. AUG(1039) is preceded in the 5' untranslated region by an in-frame CUG at nt 499 (CUG(499)), which could produce the 47 kDa form with a 180-residue N-terminal extension. We therefore assessed whether CUG(499) functions as an initiator. CUG(499) initiation produced the 47 kDa VEGF(165) precursor, which was processed at two sites to yield VEGF and three N-terminal fragments. When CTG(499) was mutated to CGC, the precursor and N-terminal fragments were barely detectable. Although the precursor form was predominant in VEGF(165), both CUG(499) and AUG(1039) forms were found in VEGF(121). VEGF precursor induced neither the proliferation of human umbilical vein endothelial cells nor the expression of angiopoietin 2, which can be induced by, and act with, VEGF to induce tumour angiogenesis. The precursor also adheres to the extracellular matrix (ECM), suggesting that it might be a storage form for generating active VEGF in the cell or ECM. Alternate CUG(499) and AUG(1039) initiation and processing of the inactive precursor and its products might be important in regulating angiogenesis.

Knockdown of IGF-IR by Antisense Oligodeoxynucleotide auguments the sensitivity of bladder cancer cells to mitomycin

AIM

To investigate whether insulin-like growth factor I receptor (IGF-IR) was involved in drug resistance of bladder cancer cells.

METHODS

RT-PCR was used to detect the mRNA expression of IGF-I, IGF-II, and IGF-IR in T24 cells and normal urothelial cells. Flow cytometry and MTT tests were used to assess the effect of antisense oligodeoxynucleotide (ODN) on drug sensitivities and apoptosis of T24 cells to mitomycin (MMC). Western blot was used to analyze the effect of ODN on expression of IGF-I R protein.

RESULTS

mRNA of IGF-I, IGF-II, and IGF-IR were strongly expressed in serum-free cultured T24 cell line, whereas normal urothelial cells did not express these factors/receptors or only in trace levels; knockdown of IGF-IR by antisense ODN greatly inhibited the growth of bladder cancer cells and enhanced sensitivity and apoptosis of T24 cells to MMC.

CONCLUSION

These results suggested that blockage of IGF-IR signaling might potentially contribute to the treatment of bladder cancer cells which were insensitive to chemotherapy.

[Expression and the role of vascular endothelial growth factor mRNA in nasal polyps]

OBJECTIVE

To explore the pathogenesis of nasal polyps, the aim of this study is to detect the expression of vascular endothelial growth factor (VEGF) in nasal polyp(NP) tissue, and compare these findings with normal nasal turbinate.

METHOD

We examined the expression of VEGF in human nasal polyps from patients underwent nasal polypectomy (n = 7) and nasal turbinate from patients with snoring (n = 6). VEGF mRNA expression was determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULT

VEGF mRNA expression was significantly stronger in the eight NP than in the turbinate tissue group (P < 0.05).

CONCLUSION

We conclude that VEGF expression is upregulated in NP, which suggests a potential role of VEGF in the formation and growth and recrudescence of NP.

Triptolide inhibits vascular endothelial growth factor expression and production in endothelial cells

AIM

To investigate the effects of triptolide on vascular endothelial growth factor (VEGF) expression and secretion by endothelial cells, and explore the mechanism of anti-proteinuric effect of triptolide on glomerulonephritis.

METHODS

A human umbilical endothelium derived cell line (ECV-304) from American Type Culture Collection (ATCC) was used in this study. The effects of triptolide on VEGF mRNA expression, production, and secretion induced by 12-o-tetradecanoyl-phorbol-13-acetate (TPA) were measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), flow cytometry, and enzyme linked immunosorbent assay (ELISA) respectively. The endothelial c-fos/c-jun mRNA expression were also detected by RT-PCR after treatment of triptolide.

RESULTS

VEGF mRNA expression was markedly up-regulated by TPA-stimulation. In addition, the production and secretion of VEGF in endothelial cells also increased in TPA treated cells. It was founded that triptolide inhibited VEGF mRNA expression, protein production and secretion in endothelial cells induced by TPA. Interestingly, TPA-induced c-fos/c-jun mRNA expression in endothelial cells was also inhibited by triptolide.

CONCLUSION

Triptolide is a potent inhibitor of VEGF expression and production in endothelial cells. The inhibitory effects of triptolide on VEGF expression and production can contribute to its anti-proteinuric effect on glomerulonephritis. Down-regulation of c-fos/c-jun expression in endothelial cells by triptolide is one of the mechanisms of the inhibitory effect of triptolide on VEGF expression.

Gene construction, expression, and characterization of double-copy truncated form of human insulin-like growth factor I

AIM

To increase the production of recombinant truncated form of insulin-like growth factor I [des(1-3)IGF-I], purify the expressed product, and compare its bioactivity with that of standard IGF-I.

METHODS

The second copy of des(1-3)IGF-I gene was inserted into the previously constructed pExSec1/IGF-I to form a pExSec1/2(IGF-I) expression plasmid, then the plasmid was transformed into a protease-deficient E coli strain BL21(DE3). The engineered bacteria were cultured and induced by IPTG at 12 degrees C. The expressed product was purified through ultrafiltration and Sephadex G-50 gelfiltration. The bioactivity of the preliminarily purified protein was tested by MTT method and compared with standard IGF-I.

RESULTS

The amount of des(1-3)IGF-I expressed by pExSec1/2(IGF-I) reached up to 20 % of the total soluble bacterial protein, which was higher than the amount (12 %) expressed by a single copy of pExSec1/IGF-I gene. The purity of recombinant des(1-3)IGF-I reached 49 % and 82 % after ultrafiltration and gelfiltration. The bioactivity of des(1-3)IGF-I after gelfiltration was about 77 % of standard IGF-I at the same concentration.

CONCLUSION

The yield of recombinant des(1-3)IGF-I was increased about 8 % by construction of expression plasmid with two copies of des(1-3)IGF-I gene compared with only one copy of gene, and preliminarily purified des(1-3)IGF-I showed about 77 % bioactivity compared with standard IGF-I.

[Therapeutic angiogenesis with the use of vascular endothelial growth factor 165 gene in the myocardium of miniature swine]

The purpose of the present study was to examine whether adenovirus-mediated vascular endothelial growth factor l65 (VEGFl65) can enhance collateral vessel formation of coronary artery and improve regional myocardial perfusion and function. Using a miniature swine model of chronic myocardial ischemia, the replication-deficient recombinant adenovirus vector containing complementary deoxyribonucleic acid (cDNA) for human VEGFl65 (Ad-VEGFl65) or for beta-galactosidase (Ad-Gal) was administered directly into the ischemic myocardium in the left circumflex (LCX) distribution. Myocardial perfusion and function were assessed by electrocardiogram-gated single photon emission computed tomography (SPECT) imaging and collateral vessel development of coronary artery was assessed by ex vivo coronary angiography (CAG). Four weeks after Ad-VEGF165 administration, SPECT imaging demonstrated a significant reduction in ischemic area (P<0.01) and ischemic severity (P<0.01), and a substantial improvement in left ventricular ejection fraction (P<0.01) and regional wall motion in the LCX distribution (P<0.05), as compared with that of control animals and that before administration of Ad-VEGFl65. Collateral vessel development with Rentrop Grading was also significantly greater in Ad-VEGF165 animals than in the Ad-Gal control animals (P<0.05). It's concluded that Ad-VEGFl65 can induce collateral vessel development in ischemic myocardium and result in significant improvement in myocardial perfusion and function.

Human vascular endothelial growth factor cDNA cloning and expression in osteoblasts

Human vascular endothelial growth factor (VEGF) cDNA was amplified by nested polymerase chain reaction method from the HL60 cells. Then a pCD-hVEGF165 recombinant plasmid was constructed. Rabbit osteoblasts were transfected with pCD-hVEGF165 plasmid by lipofectin mediated gene transfer. The transient expressive results were detected by immunohistochemical method. It was observed that the expression of human VEGF gene was detected 72 h after transfecting distinctly.

[Expression and characterization of human vascular endothelial growth factor in Pichia pastoris]

OBJECTIVE

To study the expression of human VEGF165 cDNA in Pichia pastoris and to obtain high-level expression of recombinant human VEGP165 (hVEGF165) with good biological activity.

METHODS

Amplifying hVEGF165 cDNA by PCR, after confirmed by DNA sequence analysis, the gene was inserted into the Pichia pastoris expression vector pPIC9K containing AOX1 promoter and a secreting signal peptides, the recombinant expression plasmid pPIC9K/VEGF165 was constructed and transformed into KM71. The multiple insert transformants were screened, fermented in flasks and induced by 1% methanol.

RESULTS

After 4 days of methanol induction, the expressed hVEGF165 came up to 30% of total proteins in supernatant by SDS-PAGE. The expressed hVEGF165 was further proved having good antigenicity and high specificity by ELISA and Western blot assay, and having good biological activity to stimulate HUVEC proliferation.

CONCLUSIONS

High-level expression of secreted hVEGF165 had been successfully achieved in Pichia pastoris expression system.

[Inhibition of growth and metastasis of human giant cell carcinoma of the lung by transfection of antisense VEGF121 cDNA]

OBJECTIVE

To explore the effects of blocking the VEGF/VEGF receptor paracrine pathway on growth and metastasis of human lung carcinoma cell line PG and to evaluate its potential application in gene therapy of cancer.

METHODS

The eukaryotic expression vectors bearing either sense-VEGF121 cDNA or antisense-VEGF121 cDNA was constructed and transfected into PG cells. In vitro and in vivo tests such as Northern blotting hybridization, Western blotting immunochemistry analysis, as well as xenografting in nude mice were used to analyze the effect of antisense-VEGF.

RESULTS

The transfectants stably expressing antisense VEGF121 were observed to produce markedly reduced 3.3 kb VEGF mRNA and 45 KD, 41 KD, 32KD VEGF proteins. When xenografted s.c. into nude mice, growth and metastasis of the antisense-VEGF transfected cell lines were greatly inhibited when compared with control cells.

CONCLUSION

Antisense VEGF gene significantly inhibited tumor growth and metastasis and may provide an experimental example for the development of antiangiogenic gene therapy.

[The expression and significance of VEGF mRNA and bFGF mRNA in the malignant neoplasms of ovary]

The expression and significance of VEGF mRNA and bFGF mRNA in the malignant neoplasms of ovary were studied by in situ hybridization technique. The results were that the positive rates of VEGF mRNA and bFGF mRNA were higher in the serous adenocarcinoma and embryonal carcinoma than that in the mucous adenocarcinoma and granulosa cell tumor. The positive rates of VEGF mRNA and bFGF mRNA were lower in the cases of clinical Stage I and without metastasis than that of clinical Stage III-IV and with metastasis. The results suggest that the expressions of VEGF mRNA and bFGF mRNA might be related to the pathological types, clinical stages, and metastasis of the malignant neoplasms of ovary and the patients who have positive expression of VEGF mRNA and bFGF mRNA might have a poor prognosis.

[Relationships between learning and memory and expression of nov gene of rats]

During the establishment of learning and memory of adult rats with active avoidance reaction expression of nov gene, nov mRNA positive neurons and NOV protein immunoreactive neurons were found in hippocampus, cingulate cortex, globus pallidus, caudate putamen and hypothalamus. The strongest positive reaction of NOV protein was observed in high ability group of learning and memory (HALM). Basic expression was found in pseudoconditioning (PC) group. The expression of NOV protein was higher in low ability group of learning and memory (LALM) than in PC group. No significant difference was detected in nov mRNA positive reaction between the three groups. The results indicate that nov gene may play an important role in learning and memory of adult rats. This regulation occurs at the level of NOV protein translation.

[Investigation of connective tissue growth factor's gene cloning]

OBJECTIVE

The human connective tissue growth factor(CTGF), as the responsive product of immediate early gene, was cloned for the investigation of cellular primary gene responded and healing repairing.

METHODS

RT-PCR was performed with the mRNA of HUVE cell stimulated, the three clones of CTGF, via mutational modified, were ligated to a complete gene that identified with sequencing.

RESULTS

The sequencing indicated that this CTGF gene contains complete coding region and the 3'-noncoding region which is difference with the reported sequence.

CONCLUSION

A new human CTGF gene was cloned.

Identification of proteins in the equine embryonic capsule

An acellular embryonic capsule envelops equine conceptuses between day 6 and day 23 after ovulation. As all of the factors mediating embryo-mother signalling must pass through the capsule, it acts like a 'mailbox'. Therefore, we have started to map the proteins in this special extracellular matrix at the interface between mother and embryo. In the present study, one- and two-dimensional gel electrophoresis were used to examine a range of proteins. Use of western blotting identified three specific proteins in the capsules of equine conceptuses recovered on day 16 after ovulation: insulin-like growth factor binding protein 3 (IGFBP-3), a 19 kDa uterine lipocalin (P19) and heparin-binding epidermal growth factor (HB-EGF). Western blotting of two-dimensional SDS-PAGE gels revealed the isoelectric points (pI values) of these proteins: IGFBP-3 was detected as the non-glycosylated 32 kDa form with two isoforms at about pI value 5.8; P19 had a pI value of 9.1; and several isoforms of HB-EGF were detected with molecular masses of approximately 28 kDa and a pI value range of 5.8-6.2. The origin of HB-EGF is not known, but IGFBP-3 is embryonic and P19 is maternal in origin and is thought to be a transport protein. In addition to playing a protective role, and probably also contributing to the mobility of the young conceptus within the uterus, the capsule may be thought of as the extracellular matrix of the embryo, which modulates the complex embryo-maternal signalling processes that take place during early pregnancy in mares.

[Expression of angiogenic factors and cell cycle regulation factors in human glioblastoma cell line SHG-44]

OBJECTIVE

To investigate the biological features and immunophenotypes of human glioblastoma cell line SHG-44 after long term passage.

METHODS

Immunohistochemistry and in situ hybridization were used to study the proliferative activity, intermediate filament protein coexistence, expressions of oncoprotein, angiogenic factors and cell cycle regulation factors.

RESULTS

After 130 to 150 passages, SHG-44 cells were weakly positive for glial fibrillary acidic protein (GFAP), but strongly positive for vimentin. The labeling index of Ki-67 and PCNA were 83.5% +/- 10.2% and 70.0% +/- 18.7% respectively. Overexpression of p21 ras, c-erbB-2, epidermal growth factor (EGF) and EGF receptor were obtained. Basic fibroblast growth factor (bFGF), FGF receptor, vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase (iNOS) were also up-regulated in this cell line. p16, p53, cdk4 and cyclin D1 could be detected in the cells and their indices were 43.1% +/- 11.2%, 20.7% +/- 6.6%, 33.1% +/- 11.4% and 29.2% +/- 4.7% respectively.

CONCLUSION

Expressive abnormalities of these growth factors, their receptors and the above oncoproteins as well as disorders of cell cycle regulation contribute to the rapid growth and high degree of malignancy of this cell line.

[Differential modulation of CINC, NOSII and ICAM- gene expression in parenchyma and non-parenchyma cells of the liver by G-CSF--possible protective mechanisms of endotoxin-associated hepatotoxicity]

In endotoxin-exposed rat livers, G-CSF caused a reduction of CINC gene transcripts in the nonparenchymal cell fraction, which might be the mechanism for attenuation of microvascular leukocyte adherence and leukocyte-dependent tissue injury, as observed upon G-CSF application in a model of endotoxin-induced hepatotoxicity.